Functional composition and super-capacitor properties of graphite oxide reduced with hot sulfuric acid

The heating of graphite oxide in concentrated sulfuric acid results in partial removal of oxygen and formation of holes with a size of ∼2 nm. The Raman scattering shows that the distance between the holes decreases with the time of processing while the temperature of the acid has no crucial effect on the defectiveness of a graphene layer. The functional composition of the reduced graphite oxide samples is studied by IR and X‐ray photoelectron spectroscopy. From the spectral analyses the longer the treatment, the larger the amount of oxygen removed from the graphite oxide. It is found that the edges of the holes are decorated with hydroxyl, carbonyl, and carboxyl groups and hydrogen. An increase in the temperature promotes formation of carboxyl groups. The influence of oxygenated groups and holes on the supercapacitor performance of reduced graphite oxide samples is checked using cyclic voltammetry measurements in an acidic electrolyte. Specific capacitance of samples depending on temperature and time of graphite oxide treatment by concentrated H2SO4. The scan rate of the potential was 5 mV s−1.